Electrical cut-out.



R. Cn COLE.

ELECTRICAL CUT-OUT. APPucATloN HLED ocr. s. 1917.-

Patented July 23, 1918.

` .271 ver! fr W gr/M7 7W STATES PATENT ormon- ROBEBT o. COLE, or HAnTronncoNNECTrcUT, AssIeNon To Tn- JonNs-Pnnfrrcom PANY, or HARTFORD, CONNECTIGUT, A CORPORATION F QONNE.GTIGUT.A

moment cur-DUT.

Specication of Letters Patent. A Patented Jl-lly 23, 1918.

K '.Appmauon mea october s, 1917. serm'no. 194,467.

To all lwhom ,it may concern.'

Beit known that I, ROBERT C. COLE, a citizen of the United States, residing at Hartford, in the county'of Hartford and State of Connecticut, have vinvented av new and useful Improvement in Electrical Cut- Outs, of which the following is a specification.

This invention relates to cut-outs 'of the fusible plug class in which the connection is made between the threadedshell of the plug and a contact in the threaded socket of the block by a fuse ofthe inclosed type.

The object of the invention is to provide a cut-out of this class which is very cheap to manufacture and assemble and which' is so constructed that the fusible link is readily renewable. l y

When the fusible link of an inclosed electric fuseis melted by an excess current. gas is generated by the volatilization of the metal, and this gas being inclosed oftentimes exerts very great internal pressure on the parts. To prevent the metal :end-caps from blowing off from the tubular insulating cas-A ing under this excess pressure with liability of injury and damage therefrom it has been considered necessary to securely `fasten the caps to the casing by threading the parts and screwing the caps onto the casing, or`b passing pins or screws through the caps into the casing or through the caps into parts fastened to the casin In attaining the object of the present inventlon the parts are so constructed and so coperate when in use that no means, such as threads, pins or screws, need be provided for securing the ca s on the casing, in fact the coaction is suc that not only are the caps held on the casing suiliciently strong to resist all internal pressure, but such close electrical contacts are made between the caps and the fusible link when the plug into which the fuse is inserted, is screwed into the socket, that alll danger of heating is eliminated, and a very cheap, safe and readily renewable structure is produced.

. Figure 1 of the accompan drawings shows a central section of afusible plug cutout which embodies this invention. Fig.`2 shows on enlarged scale a central section of the fusible member of the cut-out.v Fig. 3 shows atransverse section of the fuse on 'the plane indicated by the dotted line 3 3 on Fig.. 2. f

insulating material provided with a ocket containing a threaded metallic soc et 2. This socket is connected with binding means 3 for (the attachment of'one wire terminal and is'provided with a central contact stud l that is connected with binding means 5 for the attachment of the other wire terminal. The central Contact is insulated by a washer 6 from the'end of the socket.

The plug consists of a cylindrical body 'of insulation 7 containing a metallic shell.8, the lower end 9 of which is threaded so that it may be screwed into and ot of the threaded socket of the block. Agnv insulating sleeve 10 isn located within the lower end of the shell.

The fusible member 0f the cut-out has an insulating tube 11 which forms the casing. In a recess in each end of the opening through this tube is a metallic washer 12 which has one edge cut away. These wash? ers are loosely laid in the ends of the tube and are loosely retained in place by bending over them the ends 13 of thed'usible strip 14 which extends through the tube and-past the cut away edges of the washers. The metallic end caps 15 arel -made perfectly plain, that is, 4withoutthreads or holes for pins or screws, and are slipped upon the ends" of the tube over'which theyy loosel iit.

-These end caps hold the'bent ends o the fusible strip against the washers in the ends of the tube. No means, such as threads, pins or screws, being provided for retaining the caps in place on the ends of the tubetained therein which thecap tits. A hole 16 is desirably made through the end of the plug so that the fusible member may be pushed out when desired. A

When the threaded shell of the plug containing the usiblemember is screwed tightly into the threaded socket of the block r A end-capsv are forced `onto the tube by the engagement of one with the central contact in the socket and the engagement of the other with the closed end of the shell in the plug. This notA only holds the end-caps securely in place so that they cannot be blown on :tromthe tube by the pressure generated by the volatilization of the fusi# ble link when melted, but this also crowds the end-caps down onto the bent ends of the jfuse strip so as to firmly clamp those ends between the inner lwalls of the caps and the outer faces of the washers in the ends of the tube and thus insure very close joints which will eliminate lthe danger ofl heating the parts and allecting the accuracy of the fuse. when the structure is in use and current is owing across the junctions between the caps and the strip. .n

This construction not only eliminates.. all necessityofl" providing any means for'holding thev end-caps on the tube, thus cheapening the oost and rendering the device' easily renewable,but owing to the freedom ,of the caps 'allows close-joints to be made between `them land the 'fusible link without the provision of means for holding the washers in exact location, as is necessary when the endcaps are screwed onto the tubular casing, owing to the fact that the casing is liable to swell and then shrink "under atmospheric changes after it has been put to use.

The invention claimed is:

1. In a cut-out the combination of .a threaded metallic shell, a metallic contact at anend of and connected with the shell, a

threaded"J metallic socket for rece1ving the threaded shell, a metallic Contact at an end of and insulated from the socket, an

insulating tube itting within" the 'shell and having one end protruding there-- from, metallic washers loosely 4inserted in theends of the tube, a fusible strip extending through the tube and having its ends bent over 'the outer vfaces of the washers, and metallic caps loosely tted on the ends of the tube, said caps bein held on said tube, and caused to tight y clamp the bent ends of the fusible strip between the inner walls of the caps andthe washers in the ends of the tubeby the engagement with one cap'of the contact at the end of the shell and by the engagement with the other cap of the contact at the end of the socket when the shell is screwed into thesocket. j 2. Ina cut-out the lcombination of an nsulating tube, metallic washers loosely in- 4 serted in the ends of the tube, a fusible strip extending through the tube and having its ends bent over the outer faces of the washers, metallic caps loosely fitted on the ends of the tube, a screw plug adapted to receive said capped tube, and a screw socket adapted to receive said plug, said caps being held vonA said tube and caused to tightly clamp the Ibent ends of the fusible strip between the `into the socket, and a renewable 'fuse with loose end-caps, located between and having its parts held together by the socket and plug when the latter is screwed into the former. 1

ROBERT e. conn. 

